A bizarre incident in Japan this week serves as a not-so-gentle reminder that the oceans are still home to all manner of elusive and mysterious living things completely unconcerned with the whims of humankind. Close to ninety people were injured on Saturday, March 9 when a ferry traveling near Sado Island in the Sea of Japan collided with what has been described as a “massive marine creature.” While the Japanese authorities quickly scrambled to locate and identify the animal, no trace of it has been found.

The ferry was carrying 121 passengers and crew at the time of the incident. Following the crash, 87 people were treated for injuries including 13 who suffered serious harm such as broken bones. Upon inspection following the collision, a 15-centimeter-wide (6 inch) crack was found in the hull of the ship.

Whatever the boat hit, it was big.

The Japanese Coast Guard was quickly dispatched to the site of the crash to aid injured passengers and secure the scene, a task which included locating whatever aquatic creature or debris may have collided with the boat. While the Japan Timesreports it is believed the ferry “may have hit a whale or some other creature,” no trace of any animal was found.

It’s not uncommon for boats to strike whales in the waters of the Sea of Japan which is home to minke and humpback whales during these species’ annual migrations. Still, the fact that no remains or other traces of any whales were found suggests there is still the possibility that the boat could have collided with something far stranger. In 2015, a 3.7-meter (12.1 feet) giant squid was filmed as it swam leisurely in the shallow waters of a marina in Toyama prefecture, just south of Nigata where this latest ferry collision took place. Could a giant squid have been the culprit? Ultimately, while it’s most probable the ferry stuck a whale, it could have been anything.

The Pacific Ocean seen from space.

While this incident is far from smoking gun evidence of undiscovered large sea creatures, it does highlight the fact that we know much more about the surface of the moon than we do the bottom of the ocean. 70% of the world’s life lives beneath the seas, yet scientists believe up to two thirds of all ocean live remains undiscovered. However small, there is still a chance that this ferry in Japan may have struck something unknown in the Sea of Japan.

It’s too bad that whatever it hit is now likely broken in half at the bottom of the ocean. Rest in pieces, mystery creature. Will we be able to discover Earth’s unknown organisms before human activity wipes all of them from the face of our planet? Let’s hope not for their sake.